How To Convert Odds

Published: 23rd February 2016
- Updated: 19th November 2016

How do you convert odds into their implied probabilities? And how do you convert implied probability into the range of popular odds formats? Use our odds conversion calculator or learn the formulas behind.

Knowing how to convert betting odds can be very helpful. In fact, if you don't know how to convert betting odds into their respective implied probabilities, you're not helping your chances of coming away as a long term winner in the competitive world of sports betting. Understanding the implied probability behind the odds on offer is key to assessing the potential value in a particular betting market.

And it is just as important when assessing the value that exists with regards to specific odds on a particular outcome. If the implied probability is less than your own assessed probability of a particular outcome occurring, that outcome represents a value betting opportunity.

If, however, you want to learn how to convert odds to implied probability and how to covert implied probability to various odds formats, please read on. This article explains in detail how to convert the three most popular odds formats in the world - decimal, fractional and American - into their implied probabilities and how to convert an implied probability into either of these odds formats.

Our Odds Conversion Calculator will also convert a probability into odds. Want to know what 70% probability is represented as "Decimal Odds"? Our odds conversion tool will show you. Simply enter the probability as a percentage and our odds conversion tool will do the rest.

You can also embed this tool on any webpage by adding the above embed code at the bottom of the calculator.

How To Convert Odds: Step By Step Guide

There are three basic steps to converting odds

1. Understand the odds format by answering the question: Are the odds you want to convert Decimal, Fractional or American?

For example, "Decimal Odds" of 3.00 has an implied probability of 33.3% which can then be converted to fractional odds of 2/1.

This article discusses this process of odds conversion in detail with the use of step by step real world examples. If you're completely new to betting odds and implied probability, the video below presents a great introduction and overview.

How To Convert Odds To Implied Probability

Typically, there are three kinds of odds you will come across in the sports betting landscape.

"Decimal Odds": represented as 1.65 or 2.95 etc.

Fractional odds: represented as 5/2 or 3 to 2 'on' etc.

Moneyline odds: represented as -120 or +140 etc.

They all reflect the same thing, the return you will receive on a given amount of money placed on a bet. To convert your odds to implied probabilities or an implied probability to odds, you can either use our odds conversion calculator or do it by hand with the formulas provided below the calculator.

3.1 Converting "Decimal Odds"

"Decimal Odds" are a simple reflection of the return you will receive for each single unit placed. For example, let's say bookmaker Matchbook is offering odds of 1.65 for Manchester United to win. This means that for every 1.00 you bet on that particular outcome, you will receive a profit of 0.65 should Manchester United win.

To convert these odds to their respective implied probabilities we make a simple calculation.

Converting "Decimal Odds" to implied probability formula:

Implied probability

=

1 / "Decimal Odds"

Let's look at an example, in which Diego Costa to get a yellow card is odds 1.65.

Example: How to convert "Decimal Odds" to its implied probability

1 / 1.65

=

0.606

=

60.6%

Multiplied then by 100 to express as an implied probability percentage of 60.6%.

3.2 Converting Fractional odds

Fractional odds are generally the most traditional form of expressing betting odds. They are a simple reflection of the return you will receive for a particular amount bet.

So for example, let's say bookmaker Ladbrokes is offering odds of 5/2 for a particular horse to win an upcoming race. The odds of 5/2 (expressed as "5 to 2") means that for every 2 units that you bet, you will receive 5 back as profit. So if you bet €200 on that horse, you would have received €500 profit in return plus your original stake of €200.

Converting fractional odds into implied probability formula:

Implied probability

=

denominator / (denominator + numerator)

Let's look at an example, in which Diego Costa to get a yellow card is odds 5/2.

Example: How to convert fractional odds to its implied probability

5 / 2

=

2 / (2 + 5)

=

2 / 7

=

0.2857

=

28.57%

Multiplied then by 100 to express as a implied probability percentage of 28.57%

3.3 Converting Moneyline Odds

Moneyline odds, also known as 'American odds' are probably the most foreign odds format to those of us outside of North America. And at first they appear a little confusing. But it is helpful to understand what these odds represent especially when listening to Americans speaking about gambling odds in sports broadcasts or podcasts. So, let's see how we can convert Moneyline odds into their respective implied probabilities.

There are two instances of Moneyline odds: 'minus' moneylines and 'plus' moneylines.

The first are 'minus' moneylines. This is expressed as for example, -120. But what does this mean exactly? Well, let's say bookmaker bet365 are offering odds of -120 for the Los Angeles Lakers to win a game. This is essentially saying that to win $100 you have to bet $120. In other words, if you place $120 on that outcome, you will receive a profit of $100.

The other instance are 'plus' moneylines. This is expressed as for example +180. In this case, let's say bookmaker Winner Sports have offered odds of +180 for the New York Yankees to win a game. This simply means that if you bet $100, you will win $180.

So how do we convert the the 'minus' and the 'plus' moneyline odds into their implied probabilities? Let's start out with the 'minus' moneyline conversion:

Converting 'minus' moneyline odds into implied probability formula:

So let's take an example, in which Titanbet offers the following bet: San Diego Chargers to win against New England Patriots at odds -120.

Example: How to convert 'minus' moneyline odds to its implied probability

(- (-120) / ( (- (-120) ) + 100)

=

120 / 220

=

0.545

=

54.5%

Multiplied then by 100, we get the implied probability percentage of 54.5%.

Converting a 'plus' moneyline is a bit different. Calculating the implied probabilities on these look like this:

Converting 'plus' moneyline odds into implied probability formula:

Implied probability

=

100 / ( 'plus' moneyline odds + 100 )

So let's take an example, in which Paddy Power offers odds +180 for Los Angeles Lakers to beat Miami Heat.

Example: How to convert 'plus' moneyline odds to its implied probability

( 100 / 180 + 100 )

=

100 / 280

=

0.357

=

35.7%

Multiplied then by 100, we get the implied probability percentage of 35.7%.

4. How To Convert Implied Probability Into Odds

Knowing how to convert one form of odds to another can be helpful, especially if you have come into possession of a large amount of betting data that has odds formatted in an unfamiliar way.

To do this, we first need to convert any odds format to their implied probability. Once we have done this, the calculations are fairly straight forward.

4.1 Converting Implied Probability Into "Decimal Odds"

Converting implied probability into "Decimal Odds" formula:

"Decimal Odds"

=

100 / implied probability

Let's take an example. In this example we think that Arsenal has a 75 % probability of defeating Stoke. To calcluate our "Decimal Odds" target, we want to covert 75 % into odds:

Example: How to calculate implied probability to "Decimal Odds":

100 / 75

=

1.33

Implied probability of 75% would return "Decimal Odds" of 1.33.

4.2 Converting Implied Probability Into Fractional Odds

Convert implied probability into fractional odds formula:

Fractional odds

=

( 100 / implied probability ) -1

Let's look at an example, where we think Wayne Rooney has 25% probability of scoring a goal. In this example, the fractional odds target will be calculated as:

Example: How to convert implied probability to fractional odds:

(100 / 25) - 1

=

4 - 1

=

3

The outcome of this formula is 3, meaning we will express the odds as fractional odds = 3 to 1.

4.3 Converting Implied Probability Into Moneyline Odds

Converting implied probability into moneyline is a bit more complicated than converting it into decimal or fractional odds. The calculation depends on whether the implied probability is above 50% or below.

When the implied probability is above 50%, we make the following calculation.

5. Odds Conversion Chart

As a quick comparison guide, we've created an odds conversion chart which displays the odds and implied probability across each odds format.

Odds Conversion Chart

Implied Probability %

Decimal Odds

Fractional Odds

American Odds

99.0

1.01

1/100

-10000

98.0

1.02

1/50

-5000

97.1

1.03

1/33

-3333

96.2

1.04

1/25

-2500

95.2

1.05

1/20

-2000

94.3

1.06

3/50

-1667

93.5

1.07

7/100

-1429

92.6

1.08

2/25

-1250

91.7

1.09

9/100

-1111

90.9

1.10

1/10

-1000

90.1

1.11

11/100

-909

89.3

1.12

3/25

-833

88.5

1.13

13/100

-769

87.7

1.14

7/50

-714

87.0

1.15

3/20

-667

86.2

1.16

4/25

-625

85.5

1.17

17/100

-558

84.7

1.18

9/50

-556

84.0

1.19

19/100

-526

83.3

1.20

1/5

-500

82.6

1.21

21/100

-476

82.0

1.22

11/50

-455

81.3

1.23

23/100

-435

80.6

1.24

6/25

-417

80.0

1.25

1/4

-400

79.4

1.26

13/50

-385

78.7

1.27

27/100

-370

78.1

1.28

7/25

-357

77.5

1.29

29/100

-345

76.9

1.30

3/10

-33

76.3

1.31

31/100

-303

75.8

1.32

8/25

-313

74.6

1.33

17/50

-294

74.1

1.34

7/20

-286

73.5

1.35

9/25

-278

73.0

1.36

37/100

-270

72.5

1.37

19/50

-263

71.9

1.39

39/100

-256

71.4

1.40

2/5

-250

70.9

1.41

41/100

-244

70.4

1.42

21/50

-238

69.9

1.43

43/100

-233

69.4

1.44

11/25

-227

69.0

1.45

9/20

-222

68.5

1.46

23/50

-217

68.0

1.47

47/100

-213

67.6

1.48

12/25

-208

67.1

1.49

49/100

-204

66.7

1.50

1/2

-200

65.8

1.52

13/25

-192

64.9

1.54

27/50

-185

64.1

1.56

14/25

-179

63.3

1.58

29/50

-172

62.5

1.60

3/5

-167

61.7

1.62

31/50

-161

61.0

1.64

16/25

-156

60.2

1.66

33/50

-152

59.5

1.68

17/25

-147

58.8

1.70

7/10

-143

58.1

1.72

18/25

-139

57.5

1.74

37/50

-135

56.8

1.76

19/25

-132

56.2

1.78

39/50

-128

55.6

1.80

4/5

-125

54.9

1.82

41/50

-122

54.3

1.84

21/25

-119

53.8

1.86

43/50

-116

53.2

1.88

22/25

-114

52.6

1.90

9/10

-111

52.1

1.92

23/25

-109

51.5

1.94

47/50

-106

51.0

1.96

24/25

-104

50.5

1.98

49/50

-102

50.0

2.00

1/1

-100

49.5

2.02

51/50

102

49.0

2.04

26/25

104

48.5

2.06

53/50

106

48.1

2.08

27/25

108

47.6

2.10

11/10

110

46.5

2.15

23/20

115

45.5

2.20

6/5

120

44.4

2.25

5/4

125

43.5

2.30

13/10

130

42.6

2.35

27/20

135

41.7

2.40

14/10

140

40.8

2.45

29/20

145

40.0

2.50

3/2

150

38.5

2.60

8/5

160

37.0

2.70

17/10

170

35.7

2.80

9/5

180

34.5

2.90

19/10

190

33.3

3.00

2/1

200

31.3

3.20

11/5

220

29.4

3.40

12/5

240

27.8

3.60

13/5

260

26.3

3.80

14/4

280

25.0

4.00

3/1

300

23.8

4.20

16/5

320

22.7

4.40

17/5

340

21.7

4.60

18/5

360

20.8

4.80

19/5

380

20.0

5.00

4/1

400

19.2

5.20

21/5

420

18.5

5.40

22/5

440

17.9

5.60

23/5

460

17.2

5.80

24/5

480

16.7

6.00

5/1

500

16.1

6.20

26/5

520

15.6

6.40

27/5

540

15.2

6.60

28/5

560

14.7

6.80

29/5

580

14.3

7.00

6/1

600

13.3

7.50

13/2

650

12.5

8.00

7/1

700

11.1

9.00

8/1

800

10.0

10.00

9/1

900

9.1

11.00

10/1

1000

8.3

12.0

11/1

1100

7.7

13.0

12/1

1200

7.1

14.00

13/1

1300

6.7

15.00

14/1

1400

5.0

20.00

19/1

1900

3.3

30.00

29/1

2900

2.5

40.00

39/1

3900

2.0

50.00

49/1

4900

1.0

100.00

99/1

9900

0.7

150.00

149/1

14900

0.5

200.00

199/1

19900

Bookmaker Odds Settings

Most online bookmakers now offer alternative display options for their odds. Below you can see the odds options available at bet365. Simply check your preferred odds format and all odds in all markets offered by bet365 will appear in that format.

So let's sum it up.........

How To Convert Odds

While there are many tools on the web that will help you convert odds to their implied probabilities and convert odds to other formats, it is still a good practise to understand the calculations behind these conversions. This will only help you better understand what the odds represent in terms of value as well as exercising your betting brain to think instinctively in terms of implied probabilities when odds are presented to you.